Collines is one of the twelve departments of Benin. The departments that border Collines are Plateau, Borgou, Zou, and Donga. The main ethnic groups in the department according to the National population census are Yoruba of the Nagot group at 46.8% and the Yoruba of the Idasha at 14.9% for a total of 61.7% to constitute the majority, the Yoruba group is followed by the Mahi at 25.7% or just over a quarter of the regional population, while the Fon represent 13% of the population.